package algs35;
import stdlib.*;
import java.io.File;
/* ***********************************************************************
 *  Compilation:  javac FileIndex.java
 *  Execution:    java FileIndex file1.txt file2.txt file3.txt ...
 *  Dependencies: ST.java SET.java In.java StdIn.java StdOut.java
 *  Data files:   http://algs4.cs.princeton.edu/35applications/ex1.txt
 *                http://algs4.cs.princeton.edu/35applications/ex2.txt
 *                http://algs4.cs.princeton.edu/35applications/ex3.txt
 *                http://algs4.cs.princeton.edu/35applications/ex4.txt
 *
 *  % java FileIndex ex*.txt
 *  age
 *   ex3.txt
 *   ex4.txt
 * best
 *   ex1.txt
 * was
 *   ex1.txt
 *   ex2.txt
 *   ex3.txt
 *   ex4.txt
 *
 *  % java FileIndex *.txt
 *
 *  % java FileIndex *.java
 *
 *************************************************************************/

public class FileIndex {

  public static void main(String[] args) {
    args = new String[] { "data/ex1.txt", "data/ex2.txt", "data/ex3.txt", "data/ex4.txt" };
    StdIn.fromString ("age best was");

    // key = word, value = set of files containing that word
    ST<String, SET<File>> st = new ST<>();

    // create inverted index of all files
    StdOut.println("Indexing files");
    for (String filename : args) {
      StdOut.println("  " + filename);
      File file = new File(filename);
      In in = new In(file);
      while (!in.isEmpty()) {
        String word = in.readString();
        if (!st.contains(word)) st.put(word, new SET<>());
        SET<File> set = st.get(word);
        set.add(file);
      }
    }


    // read queries from standard input, one per line
    while (!StdIn.isEmpty()) {
      String query = StdIn.readString();
      StdOut.println(query);
      if (st.contains(query)) {
        SET<File> set = st.get(query);
        for (File file : set) {
          StdOut.println("  " + file.getName());
        }
      }
    }

  }

}